1. Field of the Invention
The present invention relates to a disposable set for establishing a fluid connection between a fluid dispensing unit and a dosing device adapted to dispense the fluid into a patients' vein, wherein the disposable set essentially consists of a length of a tubing for establishing a fluid connection from the dispensing unit towards and into the dosing device, according to the preamble of the first claim.
2. Description of the Related Art
Contrast medium dispensing systems are well known in the art. The known dispensing systems usually comprise a spike at one end for engaging the reservoir containing the contrast medium, and on the other end a mechanism with a luer connector for coupling the container to one port of a manifold. Another port of the manifold is coupled to a syringe adapted to administer the fluid into the patient's vein. To reduce waste, many contrast medium dispensing systems include a reservoir between the spike and the luer connector to temporarily hold a quantity of contrast medium. In an effort to avoid cross contamination between patients, many systems include a reusable set carrying the spike and a disposable set carrying the outlet luer connector providing the connection to the syringe, a pair of mating luer connectors for selectively joining the reusable and disposable set and a check valve downstream the spike. By switching the disposable set, one large container of contrast medium may be used with multiple patients.
An example of a contrast fluid dispensing system is disclosed in U.S. Pat. No. 6,800,072. The dispensing system disclosed in U.S. Pat. No. 6,800,072 comprises a tube with a first end connected to a spike adapted to be coupled in fluid communication to a bulk source of contrast media. A second end of the tube comprises a first part of a luer connector which is provided to co-operate with a corresponding second part of the luer connector mounted to a disposable set. The disposable set comprises a reservoir which is in fluid connection with a further tubing which is adapted to conduct the contrast medium from the reservoir to a port of a manifold through a one-way valve. A syringe for delivering the contrast medium into the patients' vein is connected to an administering tubing which is connected to another port of the manifold. The reservoir comprises a cap member which is adapted to reduce the risk to splattering and the ensuing formation of bubbles in the reservoir.
The dispensing device disclosed in U.S. Pat. No. 6,800,072 however presents the disadvantage that it does not permit to check in the vicinity of the syringe whether or not the syringe been well inserted into the patients' vein, and does not permit to establish whether or not the contrast medium is actually flowing into the patients' vein and not into the surrounding tissue. Besides this the dispensing device of U.S. Pat. No. 6,800,072 does not contain any means which inhibit back flow of blood from the patients' vein towards the reservoir containing the contrast medium and further towards the bulk source. Such a back flow is to be avoided as it is a basis of contamination of the system, where a next patient may be contaminated with foreign material, possibly from a former patient.
WO03/086528 discloses a one-way valve for use with tubes for medical use in particular peritoneal dialysis, which combines the functions of mechanically connecting the end parts of an infusion/drainage line and an access line connected to the peritoneum of a patient, and of regulating the flow to provide a flow with few or no areas of stagnation. Thereto the one-way valve comprises a main body with at least one fluid passage, which is attachable to the end of a first tube and which comprises an elastically deformable shut-off element to provide or prevent fluid communication between the end parts of the fluid passage. The elastically deformable shut-off element has a longitudinal axis of symmetry and is designed to deform symmetrically during the transition from a first condition where fluid communication is prevented, and a second condition where fluid communication is permitted. However, as the one-way valve of WO03/086528 is provided for use in peritoneal dialysis, verification of correct insertion of the access line into the peritoneum is not a problem which is addressed.
U.S. Pat. No. 5,593,385 discloses a dispensing system for introducing contrast media intravascularly during catherization procedures. The system comprises a first tubing segment which on one end is provided with a spike connecting the first tubing segment to a bottle containing the contrast medium. The first tubing segment is connected to the second tubing segment by means of a stopcock and a luer connector. A top check valve is mounted at the end part coupling the second tubing segment to the first tubing segment to prevent reflux from the second tubing part. The second tubing part is connected to a third tubing part by means of a bottom check valve and stop cock, the bottom check valve preventing reflux from the third tubing segment to the second tubing segment. The third tubing segment is coupled to a conventional manifold and further towards the vascular system. Air may be admitted through the stopcock to enhance the flow of the contrast medium. Due to the presence of the luer connector, the second and third tubing may be dispensed after use, and the first tubing segment may be re-used. U.S. Pat. No. 5,593,385 does not disclose means which permit to check whether a syringe mounted to a tubing connecting the manifold to the patient, has been correctly inserted into the patients' vein.
In view of preventing contamination of the manifold or reservoir and the fixed part of a fluid dispensing system, there is thus a need to a dispensing device containing a tool which permits to verify whether or not a dosing device, in particular an injection needle, has been well inserted into a patients' vein in such a way that the fluid flows from the fluid dispensing system into the vein thereby minimizing the risk to dispensing of the fluid into surrounding tissue.